Contaminant Levels Decline In Fish Study Finds Lower Numbers In Fish Taken From Lake Roosevelt

A newly released federal study finds slightly reduced chemical contamination in fish from Lake Roosevelt.

None of the contaminants that led to health advisories in the 1980s and early 1990s has disappeared. The state has no plans to lift its advisory that people limit meals of fish from the Eastern Washington reservoir.

But mercury in walleye fillets decreased by about half between 1994 and 1998, said Mark Munn, research biologist for the U.S. Geological Survey.

Dioxins and furans decreased significantly in rainbow trout fillets. There was no similar decrease of the contamination in whitefish, probably because that species spends more time in backwater areas where dioxins tend to settle, Munn said.

Dioxins and furans are suspected causes of cancer and birth defects. Both are hydrocarbon compounds produced as byproducts from industrial processes such as paper-making.

The concentration of PCBs, another carcinogenic contaminant found in fish fillets, did not change during the fouryear period.

“We don’t know where the source is” for the PCBs, Munn said, adding that the contamination level found in Lake Roosevelt fish “is not unusual.”

Lake Roosevelt stretches 130 miles, from Grand Coulee Dam nearly to Canada. It is the biggest reservoir on the Columbia River, and last year drew about 1.5 million visitors, primarily for boating, fishing and camping.

The Canadian agency B.C. Environment in 1988 warned people against eating more than one meal of Columbia River walleye each week. The fish showed unhealthy concentrations of mercury. The agency issued a similar warning for whitefish after studies in 1990 and 1991 showed high levels of dioxins and furans in the fillets.

Researchers believe the pollution came primarily from the Celgar Pulp Co. mill and the Cominco Ltd. lead smelter in Canada. Both industries spent millions of dollars in the 1990s modernizing their plants. Munn said that investment was likely the single largest reason that contamination has decreased.

Reservoir drawdowns to benefit salmon in the Columbia River downstream may also have helped, he said. Water now moves through Lake Roosevelt much faster than it did in the early 1990s.

B.C. Environment in 1996 lifted its health advisory, but the Washington Department of Health remained unconvinced. The state agency in 1991 advised anglers to remove the skin and fat from Lake Roosevelt fish before cooking, keep only small fish and limit the number of meals to 20 each month.

The advisory remains in effect, said Glen Patrick, Department of Health adviser.

“There’s a lot of uncertainty about what this (the new study) means in terms of effect on human health,” he said.

Health advisers are waiting for the U.S. Environmental Protection Agency and the National Science Advisory Board to complete a study about the health effects of dioxins before deciding whether to lift the advisory, Patrick said. It’s unclear when that study will be completed.

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Forum

The Lake Roosevelt forum is hosting a conference may 23 and 24 at Cavanaugh’s Inn at the park in Spokane. Topics will include the reservoir’s fisheries, hatchery practices, pollution, habitat projects and ways that efforts to save Columbia River salmon might affect reservoir management. The forum includes government agencies, tribes, sportsmen, business leaders and landowners. Admission to the conference is free. For more information, or to register, call 509-535-7084 or send e-mail to info@irf.org.